Spider web blackening process



Unite SPIDER WEB BLACKENING PROCESS No Drawing. Filed June 10, 1957, Ser. No. 664,469 3 Claims. (Cl. 117-106) This invention has to do with the method or process of blackening to an opaque condition spider web filaments, adsorptive, and microscopically etched materials.

As is well known, spider web filaments are used as reticules in auto-collimators, gun sights and similar instruments and equipment. Auto-collimators will be here considered for the reason that this instrument, to be of extensive use, must be accurate. As a result, conditions that exist in this instrument also will be present in others when reticules are a component part.

Heretofore, auto-collimators have used spider web filaments just as they existed in the natural state. However, a major problem was present. How accurately could a reading be duplicated time after time? It was learned that duplication was extremely difficult and virtually impossible for at least one reason. The spider web filament used was transparent or translucent under a bright light. As a result there was a light reflection and re fraction problem. For instance, if the edges of the filament approach each other too closely, the diffusion of light through the filament interferes with the defining edge. The result is that the fuzzy edge obtained reduces to a considerable degree the possibility of reproducing, or duplicating, or accurately obtaining a reading.

The problem is to make the spider web filament black in order that a sharp, distinctive edge definition is present. However, the spider web filament cannot be painted, lacquered or dyed for the reason that the size will be increased and an increase in size obviously will result in providing other errors and perpetuating some that already exist. Therefore, the spider web filament must be provided with an opaque black color and at the same time the size must at least stay the same.

Additionally, objects that are believed to be colored an opaque black, in most if not all instances, are not. Careful scrutiny, with the use of a microscope will show that the blackened objects are translucent. The material used to color black does not provide a thorough complete coverage.

An object of this invention is to provide a process or method of blackening, to an opaque condition, spider web filaments, \adsorptive, and microscopically etched materials.

Another object of this invention is to provide a process or method of blackening, to an opaque condition, certain materials without changing the dimensions of the materials or in any way altering their composition or configuration.

A yet further object of this invention is to provide a method of blackening materials, to an opaque condition, that is economical, and applicable to a broad range of materials and use.

Briefly, the method of this invention comprises placing the material in an atmosphere of a reducing agent that is in a vapor pressure phase; removing the material from the atmosphere mentioned and placing it in an atmosphere of a metal oxide that is in a vapor pressure phase. When the material obtains an adequate opaque black condition tates Patent it is removed from the metal oxide atmosphere. The procedure defined may also be inverted.

The blackening of a spider web filament will be considered along with the details of the process. However, it is to be understood that what is applicable to blackening the filament is also generally applicable to any other material that is adsorptive or microscopically etched.

The filament to be used is generally obtained from the black widow spider. It is placed in an atmosphere of a reducing agent. Hydrazine, P-phenylenediamine, P- aminophenol, hydroquinone, along with potassium hydroxide and hydrazine sulphate are considered to be reducing agents having the proper properties. Other reducing agents may also be used, but those listed are considered to provide optimum results. The reducing agent is placed in any suitable container and is heated to between to 210 F. to provide a vapor pressure. This temperature and condition is maintained for approximately 30 minutes to two and one-half hours or until the spider web filament is completely saturated with the agent. However, one important feature is to be observed; the reducing agent must not condense for the reason that the filament will be destroyed or improper blackening will take place. A vapor pressure must be maintained. Attention is directed to the fact that less heat may be applied or in some cases no heat. The only diflEerence being that it will take longer to completely saturate the filament. Some conditions and circumstances may dictate the latter procedure.

Once the filament has been adequately saturated with a reducing agent it is removed from this atmosphere and placed in a container having either ruthenium tetroxide, RuO or osmium tetroxide, OsO therein. The material in the second container is heated from 70 to F. for approximately two and one-half hours, or until the filament has obtained an opaque black condition. Again, it is to be noted that no heat or less heat may be applied, and the difference would only be in the time necessary to obtain the desired results. The procedure should be slow in this step to prevent flaking.

It is a well known fact that in both cases having to do with the reducing agent and metal oxide that a vapor pressure exists even at room temperature, but the pressure is not as great as that obtained when the materials are heated.

Because the spider web filament is porous the reducing agent and metal oxide penetrate into the interior of the filament. The result is that the filament obtains in the final condition an opaque black conditions, but the dimension is not changed.

The procedure of exposing the filament to a reducing atmosphere and then to a metal oxide atmosphere may also be inverted.

Further, the entire operation can be performed under a vacuum condition.

While in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise a preferred form of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

What is claimed:

1. The method of opaque-blackening a spider web com prising exposing said web to an atmosphere of hydrazine heated to a temperature between 100 to 210 F. to provide an uncondensed vapor pressure phase; removing said web from said atmosphere after an exposure period between thirty minutes to two and one-half hours; and placing the web in a container and exposing said web for about two and one-half hours to an atmosphere of ruthenium tetroxide heated to a temperature between 70 to 140 F.

2. The method of opaque-blackening a spider web comprising exposing said web to an atmosphere of hydrazine heated to a temperature between 100 to 210 F. to provide an uncondensed vapor pressure phase; removing said web from said atmosphere after a predetermined exposure period; and placing the web in a container and exposing said web for about two and one-half hours to an atmosphere of ruthenium tetroxide heated to a temperature between 70 to 140 F.

3. The method of opaque-blackening a spider Web comprising exposing said web to an atmosphere of hydrazine heated to a temperature between 100 to 210 F. to provide an uncondensed vapor pressure phase; removing said Web from said atmosphere after an exposure period between thirty minutes to two and one-half hours; and placing the web in a container and exposing said web for a predetermined period of time to an atmosphere of ruthenium tetroxide heated to a temperature betwen 70 to 140 F. 1

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Mellor: Comprehensive Treatise on Inorganic (copy in Div. 59), and Theoretical Chemistry, vol. 15, 1936, pages 519-521, 710, and 712. 

1. THE METHOD OF OPAQUE-BLACKENING A SPIDER WEB COMPRISING EXPOSING SAID WEB TO AN ATMOSPHERE OF HYDRAZINE HEATED TO A TEMPERATURE BETWEEN 100* TO 210*F. TO PROVIDE AN UNCONDENSED VAPOR PRESSURE PHASE, REMOVING SAID WEB FROM SAID ATMOSPHERE AFTER AN EXPOSURE PERIOD BETWEEN THRITY MINUTES TO TWO AND ONE-HALF HOURS, AND PLACING THE WEB IN A CONTAINER AND EXPOSING SAID WEB FOR ABOUT TWO AND ONE-HALF HOURS TO AN ATMOSPHERE OF RUTHENIUM TETROXIDE HEATED TO A TEMPERATURE BETWEEN 70* TO 140*F. 